<!DOCTYPE html>
<html >
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>计算器</title>
    <style>
        table{
            border-collapse: 4px;
            background-color: rgb(171, 182, 194);
            margin: 2px ;
        }
        th,td{
            border: 1px solid ;
            text-align: center;
            cursor :pointer; 
        }
        td:hover{
background-color: peru;
        }
    </style>
</head>
<body>
    <table>
        <tbody>
        <tr>
             <td>MC</td>
            <td>MR</td>
            <td>MS</td>
            <td>M+</td>
            <td>M-</td>
        </tr>
        <tr>
            <td> </td>
            <td>CE</td>
            <td>C</td>
            <td>+_</td>
            <td> </td>
        </tr>
        <tr>
            <td>7</td>
            <td>8</td>
            <td>9</td>
            <td>/</td>
            <td>%</td>
        </tr>
        <tr>
            <td>4</td>
            <td>5</td>
            <td>6</td>
            <td>*</td>
            <td> </td>
        </tr>
        <tr>
            <td>1</td>
            <td>2</td>
            <td>3</td>
            <td>-</td>
            <td rowspan="2">=</td>
        </tr>
        <tr>
            <td colspan="2">0</td>
            
            <td>.</td>
            <td>+</td>
            
        </tr>
    </tbody>
    </table>
</body>
</html>